1. Field of the Invention
The present invention relates to packaged power transistors and power packages or modules.
2. Description of the Related Art
In the art a plurality of electronic arrangements or systems relating to so called power packages, e.g. DC/DC converter or battery charger, are known. These power arrangements often comprise topologies comprising a so called H-bridge configuration comprising two half-bridges. In some instances the electronic arrangements comprises a plurality of half-bridges arranged parallel connected to each other (i.e. a parallel configuration) wherein the half-bridges may be controlled in such a way that the different half-bridges provide power signals having different phases or are out of phase in order to reduce ripples of a resulting power signal.
An example of such an H-bridge configuration of transistors is shown in FIG. 3. In particular, FIG. 3 shows an H-bridge arrangement 300 comprising four transistors, e.g. bipolar transistors, 301, 302, 303, and 304 each comprising two controlled terminals 305 and 306, respectively, and one control terminal 318. Such a configuration is often used as a switching power supply or as a DC/DC converter in the automotive technology. One of the controlled terminal 305 of the first and second transistors 301 and 302 is connected to a first voltage level of a voltage source 307 while the other one of the controlled terminals 306 is connected to a first node 308 and second node 309, respectively. A first controlled terminal 306 of the third transistor 303 is connected as well to the first node 308 while a first controlled terminal 306 of the fourth transistor 304 is connected to the second node 309. The second controlled terminals 306 are connected to a second voltage level of the voltage source 307. The first node 308 and the second node 309 are connected to a primary part of a transformer 310 while outer terminals of the secondary part of the transformer 310 are connected via diodes 311 and 312 to a corresponding third node 313. A middle terminal of the secondary part of the transformer 310 is connected to a first voltage output terminal 314. The third node is connected to a second voltage output terminal 315 via a filter circuit comprising an inductor 316 connected in series and a capacitor 317 connected in parallel.
Additionally, each of the four transistors comprises a diode 319 connected between the two controlled terminals 305 and 306 of each transistor and functioning as a protection for the four transistors.
A typical power level of such transformers is in the order of 3.5 kW while the switching frequency is in the range of 100 kHz and the voltage level is in the order of a couple of hundreds volts.
FIG. 4 depicts a schematic circuit diagram of a power package 400 comprising a first transistor 401, a second transistor 402, a third transistor 403 and a fourth transistor 404. The transistors are field-effect transistors and each comprising a source terminal S and a drain terminal D and a gate terminal G. Furthermore, the power package 400 comprises a first driving unit 405, a second driving unit 406, a third driving unit 407 and a fourth driving unit 408. Each of the fourth transistors 401 to 404 is connected to a respective one of the driving units 405 to 408. In particular, the source terminals of each of the four transistors are connected to a respective driving unit and the gate terminals of each of the four transistors are connected to the respective driving unit. Additionally the drain terminals of the first transistor 401 and the third transistor 403 are connected to a first voltage level 409 and the drain terminals of the second and of the fourth transistor are connected to the source terminals of the first transistor and the third transistor, respectively. Furthermore, the source terminals of the second transistor 402 and of the fourth transistor 404 are connected to a second voltage level 410.
While providing a working power package there may still be room for improvements.